Blame the popularity of hybrids and those new electric cars about to hit the streets. They help cut down on air pollution - and it turns out - noise pollution too and that's the problem. They're so quiet at low speeds that pedestrians sometimes can't hear them coming doubling the risk of an accident.
A bill now being considered would force carmakers to add artificial noise to these vehicles. Nissan is experimenting with a whirring sound and a bell for its electric Leaf. GM is looking at a subtle "chirp" for the Chevy Volt.
Some people object, saying it would only add to the din of city streets. But it may be a necessary speed bump ... to make sure those fuel-efficient cars aren't just better for the air...but also safer down on the ground.
That's a page from my notebook.
I'm Katie Couric, CBS News.